Nanostructured neutron sensitive materials for well logging applications

Patent metadata

Field	Value
Publication number	US-9335436-B2
Application number	US-201314026506-A
Country	US
Kind code	B2
Filing date	Sep 13, 2013
Priority date	Sep 13, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

An apparatus for estimating a property of an earth formation includes: a neutron source disposed in a borehole; a neutron detector having a neutron detection material that includes a material transparent to light having a plurality of nano-crystallites where each nano-crystallite in the plurality has a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes atoms of a neutron interaction material that emit a charged particle upon absorbing a received neutron and atoms of an activator material that provide for scintillation upon interacting with the charged particle to emit light photons wherein the atoms of the neutron interaction material and the atoms of the activator material have positions in the periodic crystal structure of each nano-crystallite in the plurality; a photodetector that receives the photons and provides a signal correlated to the photons; and a processor to estimate the property using the signal.

First claim

What is claimed is:

1. An apparatus for estimating a property of an earth formation penetrated by a borehole, the apparatus comprising:
a carrier configured to be conveyed through the borehole;
a neutron source disposed on the carrier and configured to irradiate the formation with neutrons;
a neutron detector disposed at the carrier and comprising a neutron detection material, the neutron detection material comprising a material transparent to light having a plurality of nano-crystallites where each nano-crystallite in the plurality has a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes atoms of a neutron interaction material that emit a charged particle upon absorbing a received neutron and atoms of an activator material that provide for scintillation upon interacting with the charged particle to emit light photons wherein the atoms of the neutron interaction material and the atoms of the activator material have positions in the periodic crystal structure of each nano-crystallite in the plurality;
a photodetector optically coupled to the neutron detection material and configured to detect the light photons emitted from the scintillation and to provide a signal correlated to the detected light photons; and
a processor configured to estimate the property using the signal.

2. The apparatus according to claim 1 , wherein each nano-crystallite in the plurality has a diameter or dimension in a range of 50 to 150 nm.

3. The apparatus according to claim 1 , wherein the neutron detection material comprises a glass system containing the plurality of nano-crystallites.

4. The apparatus according to claim 3 , wherein the glass system comprises A1203-Li20-SiO2.

5. The apparatus according to claim 1 , wherein the neutron interaction material in each nano-crystallite comprises Lithium.

6. The apparatus according to claim 1 , wherein the activator material comprises Cerium.

7. The apparatus according to claim 1 , where two or more of the nano-crystallites in the plurality are in contact with each other.

8. The apparatus according to claim 1 , wherein the carrier comprises a wireline, a drill string or coiled tubing.

9. A method for estimating a property of an earth formation penetrated by a borehole, the method comprising:
conveying a carrier through the borehole;
irradiating the formation with neutrons emitted from a neutron source;
receiving neutrons resulting from interactions of the emitted neutrons with the formation using a neutron detector, the neutron detector comprising a neutron detection material comprising a material transparent to light having a plurality of nano-crystallites where each nano-crystallite in the plurality has a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes atoms of a neutron interaction material that emit a charged particle upon absorbing a received neutron and atoms of an activator material that provide for scintillation upon interacting with the charged particle to emit light photons wherein the atoms of the neutron interaction material and the atoms of the activator material have positions in the periodic crystal structure of each nano-crystallite in the plurality;
receiving the light photons emitted by the scintillation using a photodetector to produce a signal; and
estimating the property using a processor that receives the signal.

10. The method according to claim 9 , wherein a diameter or dimension of each of the nano-crystallites in the plurality is at least four times smaller than a wavelength of light emitted by the scintillation.

11. The method according to claim 9 , wherein each crystallite in the plurality has a diameter or dimension in a range of 50 to 150 nm.

12. A method for fabricating an apparatus for estimating a property of an earth formation penetrated by a borehole, the method comprising:
disposing a neutron source configured to irradiate the formation with neutrons on a carrier configured to be conveyed through the borehole;
disposing a neutron detector comprising neutron detection material on the carrier, the neutron detection material comprising an optically transparent material having a plurality of nano-crystallites where each nano-crystallite in the plurality has a periodic crystal structure with a diameter or dimension that is less than 1000 nm and includes atoms of a neutron interaction material that emit a charged particle upon absorbing a received neutron and atoms of an activator material that provide for scintillation upon interacting with the charged particle to emit light photons wherein the atoms of the neutron interaction material and the atoms of the activator material have positions in the periodic crystal structure of each nano-crystallite in the plurality;
disposing a photodetector on the carrier, the photodetector being optically coupled to the neutron detection material and configured to detect the light photons emitted from the scintillation and to provide a signal correlated to the detected light photons; and
coupling a processor to the photodetector, the processor being configured to receive the signal and to estimate the property using the signal;
wherein the neutron detector material having the plurality of nano-crystallites is fabricated by a method comprising:
mixing the optically transparent material, the neutron interaction material, and the activator material together to form a mixture; and
subjecting the mixture to a heat treatment process that includes a plurality of time intervals having a corresponding temperature profile.

13. The method according to claim 12 , wherein each time interval has a temperature profile that is different from the other temperature profiles.

14. The method according to claim 12 , further comprising mixing petalite nano-particles in the mixture before subjecting the mixture to the heat treatment process.

15. The method according to claim 12 , wherein the plurality of time intervals comprises at least seven time intervals.

Assignees

• Korjik Mikhail
• Federov Andrei
• Vasilyev Maxim
• Nikitin Anton
• Baker Hughes Inc

Inventors

• Korjik Mikhail
• Federov Andrei
• Vasilyev Maxim
• Nikitin Anton

Classifications

• Y10T29/49117

  Conductor or circuit manufacturing · CPC title

• G01T3/06 Primary

  with scintillation detectors · CPC title

• G01V5/107

  and detecting reflected or back-scattered neutrons · CPC title

• G01V5/10 Primary

  using neutron sources {(neutron generating tubes H05H5/00; neutron sources using isotopes G21G4/00)} · CPC title